Plastic bags can be manufactured in an assembly line process yielding pads of bags formed by stacks containing a plurality of bags in each stack by cutting, and welding a flattened plastic foil tube to form the bags, stacking the bags and heat sealing the bags together at one side. Generally the flattened plastic tube is cut and welded transverse to its tube axis into the individual plastic bag segments.
An apparatus for stacking and padding plastic bags (i.e. sealing the bags of a stack together at one side) usually comprises a welding and cutting station, a pin conveyor belt with a plurality of longitudinally spaced stacking pins, and a delivery mechanism. The delivery mechanism usually comprises a plurality of suction arms extending essentially radially from a hub in rows transverse to the transport direction of the bags. The arms rotate about a horizontal axis. The delivery mechanism takes the individual plastic bag segments formed by the welding and cutting station and also previously formed with at least one pin hole therein and stacks them on the pin conveyor belt with the pin holes being traversed or spindled by the stack pins.
In the stacking and sealing apparatus of this type described in German patent document - open application DE-OS No. 31 38 221 two delivery suction arms are positioned next to each other with a spacing. One arm is movable past the pin conveyor belt on one side of it, while the other arm is movable past the pin conveyor belt on its other side.
Both these delivery suction arms grip a bag segment of the flattened plastic foil tube, which will be cut down its its center later in the process to produce twin plastic bags.
The twin plastic bags are delivered to and suspended from the pin conveyor belt from two rows of pins positioned next to each other. After the bag-separation and welding operation by a tool which extends in the transport direction of the pin conveyor belt and works between each row of stacking pins, two stacks or pads are obtained.
This known stacking and padding apparatus can only work following a machine which is set up for forming twin or doubled plastic bag segments from the flattened plastic foil tube.
However numerous machines exist in practice which form individual plastic bags from a flattened plastic foil tube.